Open the Setup Assistant and navigate to the 'Location Logos' Step in the 'Organization' Section

Click the 'Upload Logo' button for the desired Location

Use the file picker to locate the Logo file and upload

Via Location Record

Open the Location Record and click the 'Select Logo' button (ensure you click this button and not the 'Upload File' button. Files upload to the Location Record will not be displayed as Location Logos in Accounts Receivable)